1. Field of the Invention
The present invention relates to a digital-to-analog converter (DAC), and more particularly, to a DAC that is realized by a plurality of pulse width modulation (PWM) units, and a method thereof.
2. Description of the Prior Art
A digital-to-analog converter (DAC) is a device that converts a digital input value into a corresponding analog output voltage, which is then supplied to a backend circuit. For example, in a television (TV) system, after the user has chosen a TV channel, the TV system determines a digital input value according to the chosen TV channel. A DAC is utilized to convert the digital input value into an analog output voltage, which is then supplied to a TV tuner and allows the TV tuner to process received TV signals accordingly.
With technological advances, electrical products demand higher and higher resolutions on DACs. More specifically, a DAC is required to generate an accurate analog output voltage according to a digital input value with increased bit counts. However, the cost of a high resolution DAC is usually much higher than that of a low resolution DAC. Since cost is always a critical concern when manufacturing electrical products, reducing the costs of high resolution DACs has becomes a desire of manufacturers of electrical products.